This invention is in the field of ignition systems and more particularly in such systems that utilize alternating current as the principal power input to an ignition transformer.
Prior art systems generally involve the use of a keyed DC power source such as a battery in order to precharge the primary winding of an ignition transformer, and to subsequently discharge such primary winding into a capacitor so as create a transient current in the primary winding. Such system is generally referred to as the Kettering system, and suffers from a low energy level being fed to an igniter to fire same.
Other prior art systems, while utilizing AC power to feed such igniter, are unable to deliver a sufficiently high current to the ignition transformer primary winding or to the secondary winding thereof for feeding the igniters, and likewise suffer from low energy levels being delivered to the igniters.
Should the problem of low energy level ever be resolved, such prior art systems will still fail to perform satisfactorily when AC powered, since at higher power and energy levels, the waveforms of voltage and current during a firing cycle could not be accurately controlled as to their duration, and consequently successive firing cycles will produce waveforms without any discontinuities therebetween, resulting in pre-ignition of fuel in one of the engine cylinders before its appropriate time.
Additionally, the low energy problem solution by itself will not result in an effective ignition system since in addition to such higher energy, no system is available to provide large quantities of energy storage on a temporary basis for each igniter cycle and for delivery of such stored energy to help fire the igniter by means of a large quantity of arcs having a multitude of frequency components.